Thomas Gleixner <t...@linutronix.de> 于2020年8月13日周四 下午6:46写道： > > Qianli Zhao <zhaoqianlig...@gmail.com> writes: > > Please start the first word after the colon with an upper case letter. > > > do_init_timer can specify flags of timer_list, > > Please write do_init_timer() so it's entirely clear that this is about a > function. > > > but this function does not expect to specify the CPU or idx. > > or idx does not mean anything unless someone looks at the > code. Changelogs want to explain things so they can be understood > without staring at the code.
will update changelog > > If user invoking do_init_timer and specify CPU, > > The result may not what we expected. > > Right. And which caller exactly hands in crappy flags? This change is more of a sanity check to avoid these wrong use > > E.g: > > do_init_timer invoked in core2,and specify flags 0x1 > > final result flags is 0x3.If the specified CPU number > > exceeds the actual number,more serious problems will happen > > More serious problems is not a really helpful technical explanation and > 0x3 does not make sense for a changelog reader either because it again > requires to look up the code. > > > timer->entry.pprev = NULL; > > timer->function = func; > > - timer->flags = flags | raw_smp_processor_id(); > > + timer->flags = (flags & ~TIMER_BASEMASK & ~TIMER_ARRAYMASK) | > > raw_smp_processor_id(); > > If the caller hands in invalid flags then silently fixing them up is > fundamentally wrong. So this wants to be: > > if (WARN_ON(flags & ~TIMER_INIT_FLAGS)) > flags &= TIMER_INIT_FLAGS; > > and TIMER_INIT_FLAGS wants to be exactly the set of flags which are > valid for being handed in by a caller, i.e.: > > TIMER_DEFFERABLE, TIMER_PINNED, TIMER_IRQSAFE This change is very good，thanks for teaching > Guess what happens when the caller hands in TIMER_MIGRATING? If TIMER_MIGRATING is set in timer_setup, lock_timer_base will fall into a dead loop > If we do sanity checking then we do it correct and not just silently > papering over the particular problem which you ran into. Thanks for teaching. I have updated patchset,please review. > Thanks, > > tglx
